1. Field of Invention
The present invention relates to a holographic aligner for exposure with a hologram and, more particularly, to an aligner and an exposing method suitable to expose part of a hologram mask.
2. Description of Related Art
In a semiconductor-device patterning process, a related art total-internal-reflection (TIR) holographic exposing technique has come to attract attention. The exposing technique includes a recording process of recording a desired pattern in a hologram and an exposing process of irradiating the hologram mask with regenerated light to expose a photoresist for a semiconductor pattern to light.
In the recording process, a laser recording beam is applied to a mask pattern (original reticle), corresponding to the pattern of a semiconductor device, to generate diffracted light and irradiate the recording surface of a hologram mask. Reference light is applied to the recording surface of the hologram mask from the back at a fixed angle to interfere with the diffracted light from the original reticle, thereby generating an interference pattern on the recording surface of the hologram mask and recording the interference pattern on the hologram recording surface.
In the exposing process, the hologram mask is placed at the same position as that of the original reticle to irradiate it with an exposure beam, or regenerated light, from the opposite direction of that used in the recording process to image the diffracted light that reproduces an original pattern on a photoresist, to thereby expose the photoresist to light.
The exposure beam used in the exposing process is generally adapted to scan the entire surface of the hologram mask. In order to expose only part of the hologram mask, a douser as large as the hologram mask is generally used.
Alternatively, only part of the hologram mask maybe exposed by controlling the scanning area of the exposure beam.